Tropical fever in remote tropics: tuberculosis or melioidosis, it depends on the lab

Abstract

Diagnostics tests used to identify the cause of infection using proteomics and genomics have revolutionised microbiology laboratories in recent times. However, approaches to build the capacity of clinical microbiology services in the rural tropics by simply transplanting these approaches have proven difficult to sustain. Tropical fever in the remote tropics is, by definition, a clinical diagnosis where the aetiology of fever is not known, treatment is empirical, guided by clinical suspicion with treatment failure often attributed to incorrect diagnosis or antimicrobial resistance. Tuberculosis (TB) in rural Papua New Guinea (PNG) is mostly diagnosed clinically, perhaps supported by microscopy. In fact, a ‘tuberculosis patient’ in rural PNG is included in the TB register upon commencement of TB treatment with or without any laboratory-based evidence of infection. The roll-out of GeneXpert is continuing to transform TB diagnostic certainty in TB endemic communities. Melioidosis is endemic in tropical regions and is increasingly reported to mimic TB. Isolation and identification of the causative agent Burkholderia pseudomallei remains the gold standard. Here, we discuss the increasing divide between rural and urban approaches to laboratory-based infection diagnosis using these two enigmatic tropical infectious diseases, in rural PNG, as examples.

Melioidosis and Burkholderia pseudomallei: progress in epidemiology, diagnosis, treatment and vaccination

“…Much of the uncertainty may still be attributed to the continuing lack of or limited access to microbiological laboratory diagnostic facilities and concomitant disease-reporting systems, but it is also possible that the global cases numbers and mortality are substantially lower than the estimated numbers. The ongoing disparity in access to laboratory resources has been documented in a review of diagnosis of melioidosis and tuberculosis from Papua New Guinea, where the divide between urban and rural capabilities is stark and reflects the reality of much of the Asia Pacific region and elsewhere globally [11 ▪ ].…”

“…A notable finding in Brazil is a relatively high proportion of cases of melioidosis occurring in children, with severe disease and high mortality [27 ▪ ]. Further studies are required to ascertain if and why childhood melioidosis may be more severe in Brazil than reported elsewhere, with analogies to the situation in rural Papua New Guinea [11 ▪ ].…”